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knowledge center: steam conservation & safety

These tips can help you keep your heating and cooling systems operating safely and efficiently. If you choose to pursue any of these measures, we recommend that you review them with a qualified engineer to assure that they are properly implemented. Please e-mail us at steam@coned.com if you need more information or have questions. We also welcome your suggestions about what tips and information to include here in the future. For tips on reducing on-peak steam demand, including STEEMs implementation, check out our reducing on-peak steam demand tips.

TIPS TO CONSERVE STEAM

Tip: Consider Using Condensate to Preheat Domestic Hot Water
Condensate can be used to preheat domestic hot water through a heat exchanger. This will not only offset steam consumption, but will also reduce the amount of water used to temper the condensate before it is discharged into the sewer. For guidance sketches on installing this measure in your facility, as well as other condensate reuse measures, click here.

Tip: Insulate Steam and Condensate Pipes
Keep your steam pipe system operating safely and efficiently with regular inspections by a qualified operating engineer or heating contractor. Make sure that pipes are properly insulated. Insufficient or damaged pipe insulation causes excessive heat loss and condensate build-up that can result in pipe failure. Since valves and fittings have relatively large surface areas from which heat radiates, insulating them, as well as the piping, will provide energy savings and protection from burns. Consideration should be given to removable insulation jackets around valves and other components. Condensate lines and related equipment should be insulated, especially if heat from condensate is being recovered.

Tip: Periodically Test Steam Traps
All steam traps should be tested or inspected for proper operation on a schedule recommended by the manufacturer. A clogged trap or a trap that fails in the closed position may cause harmful water hammer, which could result in property damage and/or bodily injury. On the other hand, a trap that fails in the open position, not only wastes energy but also creates a heat condition. A failed open trap with an equivalent 1/8" size orifice could result in the loss of approximately 52,000 lbs of steam at 100 psig dry saturated condition per month, or approximately $1,500 per winter month. The balance of steam system components (such as valves and fittings) should also be tested or inspected periodically to promote safe and cost-efficient operation.

Tip: Minimize Steam Leaks
In addition to steam traps, steam leaks may occur in many other points of the steam system. Inspect steam lines periodically to ensure that pressure relief valves are not leaking. Furthermore, ensure that there are no visible steam leaks into the building spaces.

Tip: Apply Outdoor Temperature Reset
If your building uses circulating hot water for space heating, resetting the water temperature supply set point based on outdoor air temperature will not only improve comfort conditions, but will also reduce steam consumption during the mild winter days. Instead of having constant water temperatures regardless of the outdoor air temperature, water temperature should be higher on cold days and lower on mild days. If you are already resetting your water temperatures, consider shifting your reset schedule down for increased steam savings.

Tip: Isolate Unused Steam Lines
Energized steam lines, even if insulated, lose heat to their surroundings. To minimize losses, any steam lines not in use should be isolated, and condensate from those lines should be drained. For example, piping that supplies steam to steam-driven chillers should not be energized in the winter if the chillers are not in use over an extended period.

Tip: Minimize Heat Loss Through the Building Envelope
Locations of thermal losses through the building envelope should be identified using techniques such as thermography. Ensure that the outside air dampers are not leaking air when closed. Identified leak locations should be sealed to minimize losses.

Tip: Adjust Domestic Hot Water Temperature
Check domestic (or service) hot water temperature at taps to ensure that it does not exceed 120°F. Water at high temperature may not only be unsafe, but also wastes energy.

Tip: Install Thermostatic Radiator Valves
Thermostatic radiator valves provide individual zoning control at the radiator level. The occupant can select and set different temperature set points to meet individual comfort levels within each room. Since the valve operation is controlled by the thermostatic element within the valve, once the settings are selected and set, there is no need to manually open and close the steam supply valve to control temperature. Installation of these valves in overheated rooms will eliminate discomfort and may provide significant savings.
Tip: Maintain Vacuum in the Steam System, if Intended
If your steam system was designed to operate under vacuum, ensure that vacuum operation is not compromised. Vacuum operation helps reduce steam consumption and ensures that condensate is drained properly. Typical reasons for the loss of vacuum include poor maintenance of steam traps, leaks in piping, and vacuum pumps that are not working properly.

Tip: Install a Programmable Building Management System (BMS)
A programmable computerized BMS may not only help improve comfort conditions in your building, but may also reduce energy consumption. Using a BMS, it is possible to monitor and trend operational data. It is also possible to automate various control strategies to reduce energy consumption, thereby allowing the operating personnel to concentrate on other tasks.
Tip: Consider Installing and Operating High-Efficiency Steam-Based Chillers
Customers can take advantage of our high-pressure steam by installing two-stage absorption chillers, and turbine-driven chillers, which require approximately 40% less steam than low pressure steam absorption chillers to meet the same cooling load. Also, if you have an all-electric plant, it may be cost effective to replace one of the existing electric chillers with a steam chiller. A steam chiller may be operated during electric on-peak times to shave electric demand and realize operating savings. Con Edison offers economic incentives to promote the installation and operation of steam-based cooling equipment. Please call the Steam Business Development Group at 1-212-460-2011 for information on available incentives for steam air conditioning.

For more information on any of these Tips see our Best Practices Report:

Tip: Manage Condensate
Condensate is water that accumulates in the pipes as the steam loses heat. It is essential that condensate be drained from the steam pipes to ensure safety, as well as to prevent erosion of pipes and other equipment.

Make sure that condensate removal equipment, such as steam traps and drain valves, are installed at appropriate points in your steam system. A steam trap automatically removes condensate from the system. To ensure a safe and reliable steam system, check the steam trap regularly to make sure it is working properly. Drain valves are used to remove condensate from lines before turning on the steam after an outage.

Tip: Avoid Delay in Service Turn-on After Repair
If you plan to change or modify your steam pipes, replace pressure reducing valve(s) or station(s), change pipe flange(s), and/or perform any repair requiring welding, please call 1-800-914-9112 or 1-212-683-8830. Steam Distribution Services will return your call to discuss the scope of work to be performed before work begins. At your request, we will arrange the shut-off of the steam service to the building. We will also advise you about New York City Building Code requirements for high pressure steam piping work, including any radiographic examination (X-ray) requirements for welding or weld repairs.

All repair work and associated documentation, such as radiographic examination reports for welding, will be reviewed by Con Edison before restoring steam service to your building. Failure to meet Building Code requirements to provide an acceptable radiographic examination report(s) will result in delays in restoring your steam service.

Please refer to the NYC Buildings Department rules on High Pressure Steam Piping Systems in the NYC Building Code, Appendix A, Chapter 20, Section 20-02. A copy of the rules will be provided upon request.

If asbestos abatement is performed, it shall be done in compliance with federal, state, and city environmental rules and regulations. We require an air clearance report(s) issued by a third party NYS-certified ELAP (Environmental Laboratory Approval Program) laboratory showing fiber count and volume of air collected. This must be done before steam service can be reactivated. This report is required for all abatement work, regardless of project size, conducted inside steam rooms or areas that require Steam Distribution personnel to enter to restore service.

During normal business hours, air clearance report(s) should be faxed to Steam Distribution Operations at 1-212-253-8910. For more information call 1-212-338-4470. During off hours, weekends, and holidays please provide hard copy reports to the steam supervisor or crew, at the time of service turn-on.

Vent lines from condensate collection vessels, such as a dilution and/or flash tank, must be kept unblocked to prevent pressure from building up. If you are a seasonal customer, please make sure that your steam equipment is thoroughly inspected before arranging for turn-on. All inspections, adjustments, and repairs to your steam piping system should be done by a qualified operating engineer or heating contractor.

Occasionally, we may have to interrupt your service to make repairs to the steam distribution system. If this happens, Con Edison will notify you in advance of the outage. If you plan to do work on your steam system during the outage, please let us know immediately by notifying the Con Edison representative who arranged the outage, or by calling either of these Con Edison emergency numbers: 1-800-914-9112 or 1-212-683-8830. As a safety precaution, we will verify that your work is complete before reactivating steam service when our repairs are finished.
Tip: Call Con Edison to Reopen the Inside Steam Service Valve
The inside steam service valve is to be closed only in an emergency. To prevent use by unauthorized persons, Con Edison has wire-sealed the valve and attached a metal warning tag which lists all emergency restrictions. It is possible that condensate may build up behind the inside service valve if it is closed. For this reason, you must arrange to have Con Edison reopen the valve by calling 1-800-914-9112 or 1-212-683-8830.

You should always follow the necessary safety measures whenever you need to close an inside steam service valve during an emergency.